Gemmology
English | Български
Where am I? > Home > Repository > Opal


Gallery view selector

Colour selector
Simple colour schemeredorangey redreddish orangeorangeorangey yellowyellowgreenish yellowyellowish greenslightly yellowish greengreenvery slightly bluish greenbluish greenvery strongly bluish greengreen-blue or blue-greenvery strongly greenish bluevery slightly greenish bluebluevioletish bluebluish violetvioletbluish purplepurplereddish purplestrongly purplish redslightly purplish redcolourlessgreyblack

Opal — specimens [gallery view] (Page 4)


Regarded as mineral species for historical reasons; not a true mineral in the accepted sense of the word as it is either composed of cristobalite and/or tridymite or of amorphous silica; sedimentary and secondary from the alteration of high silica igneous extrusive rocks. There are specimens of 2610 carats (Arem, 1987: 139).
Opal — specimen 0748
0748
Turkey
Opal — specimen 0365
0365
Ethiopia
Opal — specimen 0273
0273
Madagascar
Opal — specimen 0714
0714
Madagascar
Opal — specimen 0715
0715
Madagascar
Opal — specimen 0716
0716
Madagascar
Opal — specimen 0717
0717
Madagascar
Opal — specimen 0718
0718
Madagascar
Opal — specimen 0721
0721
Madagascar
Opal — specimen 0347
0347
Madagascar

Opal — specimens — 40
First Previous Page 4 of 4